Immune system turning on itself may trigger melanoma growth

A new study by researchers from Yale and Johns Hopkins reveals the molecular pathway by which the body's inflammatory immune response may trigger its own inhibition, protecting tumor cells from destruction and allowing the growth of melanoma - the deadliest form of skin cancer. The study currently appears in Science Translational Medicine. Although it occurs less often than other skin cancers, melanoma causes the majority of skin cancer deaths. It is often curable in its early stages, but once it has spread invasively, it is very difficult to treat. The researchers focused on a specific immune-inhibiting molecule in melanoma tumors known as B7-H1. They found that in patients whose tumors expressed B7-H1, suppression of the inflammatory immune response promoted the growth and aggressiveness of their melanoma tumors. Further, they uncovered the mechanism by which this happens: Tumor cells somehow utilize an active component of the immune response itself, interferon gamma, to turn on B7-H1 and protect themselves by suppressing the immune system.